Piston



July 20,1926.y 1,593,265

A. KUNZE PISTON Filed oct. 9, 1924 y Auguu Kunze.

Patented July 20, 1926.

UNITED STATES PATENT OFFICE.

AUGUST KUNZE, OF LAKE EULAH, WISCONSIN.

PISTON.

Application filed October 9, 1924. Serial No. 742,578.

This invention relates to improvements in mission, which keeps thepiston rings and cylinder walls in better condition, and which.

lncreases the heat in the combustion chamber while at the same timereducing the loss of heat to the smallest possible amount. Furtherobjects are to provide a piston construction and a device which may beattached to a standard type of piston which will markedly decrease thecarbonization on the upper side of the piston, which will t0 decreasethe frequency of valve grinding, and whichwill not be injured even bythe highest possible speed of the motor.

Further objects are to provide a piston construction which reducesincrustation and carbonizing of the lubricant on the lower side of thepiston, which keeps the lubricant in the crank case free from carbonizedparticles and in better condition than has eretofore been possible, andwhich decreases the consumption of oil in the crank case.

Fmbodiments of the invention are shown the accompanying drawings, inwhich Figure 1 is an elevation of a piston with t5 parts in section.

Figure 2 is a vertical sectional view through a piston showing amodified form of construction.

Figure 3 is a transverse sectional view e0 through the pistonillustrated in Figure 2 showing one of the retaining straps in positionand the other removed.

vReferring to the drawings particularly Figure 1, it will be seen thatthe piston 1 e5 is provided with an overhanging upper fiange 2 ofNannular construction and spaced from the upper piston wall 3. rlhisflange is provided with a slanting bottom surface t, as clearly shown insuch figure. An asan bestes or other heat insulating or resisting pad orwasher 5 is positioned immediately above the piston head 3. Above thisinsulating pad a metal plate 6 is provided and is equipped with slantingfaces adapted to slide bene th the slanting faces 1.1L of the Harige 2..n positioning this plate 6 it is t0n head to the crank case preferablybowed upwardly, as shown in dotted lines in Figure 1, and down intoplace. y

Thereafter, a bolt 7 is passed through the plate 6, the pad 5 andthe`piston head 3 and thus locks the parts in position at theircentenktheirl peripheral portions being locked in place by the slantingfaces et of the flange 2. It is preferable to swage the lower end of thebolt to prevent inadvertent then pressed detachment, as illustrated inFigure 1.

It has been found that the best metal for the plate 6 is copper and ithas been found from actual experimental work that this copper itselfdoes not vfavor carbonization but materially hinders it.

It is clear that the construction illustrated in Figure 1 could bemodified by making the plate 6 integral with the remaining portion ofthe system and thereafter filling the intervening space between the headand the plate with a temporarily plastic heat insulating compound, andthereafter positioning the bolt, as shown in Figure l. It is also to benoted that the plate 6 could be made circularly corrugated to providefor expansion and contraction.l

The operation of this, device will be clearly seen from the detaileddescription of its construction. It is, however, pointed out that theupper portion of the piston is subjected to the highest temperature andthat the heat is conducted through the pisand through the piston wallsto the piston rings under normal conditions. However, with thisconstruction, the heat insulating pad 5 very materially reduces the heattransmission and it has been found that it materially reduces thecrystallization of the rings and the heating of the crank case. Furtherthan this it reduces the expansion of the piston and permits the engineto run smoothly under all conditions of load.

By this construction it will be seen that carbonization is materiallyreduced both on the upper side of the piston and on the lower' sidethereof, and that the crank case oil will remain in good condition for agreat length of time and that the surrounding walls and piston ringswill be maintained in a better condition than heretofore due to the factthat heat conduction through the piston and through the rings has beenvery markedly reduced. From actual experience it has been found thatheat transmitted to the crank case has been reduced 75% by Ythisconstruction.

In the modified form shown in FiguresQ and 3 a standard type of piston 8has been provided. This piston is equipped with an asbestos of similarpad 9 on the lower side of its head, and the pad is held in place bymeans of a pair of plates 10 and 11 preferably provided with overlappingportions, as shown in Figures 2 and 3. These plates are held in placetightly against the lower side of the pad 9 by means of adjustablescrews 12, such screws passing through ears 13 of supporting curvedstraps 14.

These straps 14 fit over the inwardly pro.

jecting bosses .l5 of the piston, as clearly shown in the drawings. InFigure 3 a sectional view is shown with one of the straps 14 in placeand with the other strap removed, such view omitting the bosses 15 ofthe piston for the sake of clearness.

It is contemplated providing the plates 10 and 11 with notches 16', ifdesired, to accommodate reenforcing webs found in certain types ofpistons. It is preferable to provide the plates 10 and 11 with marginal,downwardly turned flanges 16 and 17 to increase their stiffness andstrength.

It will be seen, therefore, that means have been provided in pistonconstruction which will prevent carbonizing both on top and below thepiston,

and heat transmission through the piston, which will increase the timeduring which the crank case oil may be used Without renewal, and whichwill'guard the parts against excessive heating crystallization and othermaterial defects of this nature.

` Although the invention has been described in considerable detail, itis to be understood that the invention may be variously embodied and is,therefore, to be limited only as claimed.

I claim:

A piston comprising a body portion, a piston head, an angular flangecarried by said body portion and spaced outwardly from said head andhaving an inwardly located bevelled facefa heat insulating pad locatedupon the outer face of said piston head, an initially outwardly bowedcircular plate having a bevelled peripheral edge fitted below thebevelled face of said flange, and a bolt passing centrally through saidplate, pad and piston head and holding said plate flat.

In testimony that I claim the foregoing I have hereunto set my hand atLake Beulah, in the county of Walworth and State of Wisconsin.

AUGUST KUNZE.

which will reduce heat loss

